Niphargus bisitunicus, Esmaeili-Rineh, Somayeh, Sari, Alireza & Fišer, Cene, 2015

Esmaeili-Rineh, Somayeh, Sari, Alireza & Fišer, Cene, 2015, Making future taxonomy of Niphargus (Crustacea: Amphipoda: Niphargidae) in the Middle East easier: DELTA database of Middle East species with description of four new species from Iran, Zootaxa 4020 (3), pp. 401-430 : 403-408

Niphargus bisitunicus sp. nov.

(Figs 2–5)

Material examined and type locality. Holotype, male ZUTC Amph.2326. Sarab-e- Bisitun ( Fig. 1 ), 25 Km west of Kermanshah city, Kermanshah Province, Iran (34°25′N, 07°28′E). Three male paratypes ZUTC Amph.2345.

Diagnosis. Urosomites I–II with one and three robust setae accompanied with two simple setae along the dorso-lateral margin. Epimeral plates distinctly produced. Telson deeply cleft, each lobe with three apical robust setae, one marginal robust seta and two marginal simple setae. Propods of gnathopods I–II each with two shortrobust setae (so called supporting robust setae) in palmar corner. Dactyli of pereopods III–VII with one simple seta at outer margin.

Description of holotype. Body length 9 mm. Body stout. Head length 12% of body length. Antennae I (fig. 2A). Antenna I 0.23 of body length. Peduncular articles 1–3 progressively shorter; length of peduncular article 3 more than half of peduncular article 2; main flagellum with 22 articles (most of which with short setae); accessory flagellum bi-articulated and reaching one-third of article 2 of main flagellum; first and second articles with one and two simple setae, respectively (fig. 2A).

Antennae II (fig. 2B). Antenna II as long as 0.56 of antenna I. Peduncular article 5 slightly shorter than article 4, ratio between articles 4: 5 equal to 1: 0.9, article 5 with five groups of simple setae; flagellum with 10 articles, approximately 0.96 of length of peduncle articles 4 +5.

Labium (fig. 3B) with inner lobes.

Maxilla I (fig. 2D, E). Inner plate with two long simple setae, outer plate with seven long robust setae of which four with one, one with two and two without lateral projections; palp bi-articulated, long, with three long distal simple setae.

Maxilla II (fig. 2C). Both plates with numerous long distal simple setae, inner lobe with lateral simple setae.

Mandibular palp (fig. 2F). Ratio of mandibular palp articles 1: 2: 3 equal to 1: 1.8: 1.5, no setae on first article; second article with seven long simple setae medially; third article with one group of two A-setae, two single groups of B-setae, no C-setae, 15 D-setae and five E-setae.

Left mandible (fig. 2G). Incisor with five teeth, lacinia mobilis with two large teeth; seven setae with lateral projections between lacinia and triturative molar. Right mandible (fig. 2H). Incisor with four teeth, lacinia mobilis pluritooth; eight setae with lateral projections between lacinia and triturative molar.

FIGURE 2. Niphargus bisitunicus , sp. nov., Sarab-e- Bisitun, male 9 mm (holotype). A, A1; B, A2; C, MX 2; D–E, MX 1; F, MNDP; G, LMND; H, RMND. Scale bars: 1= 0.25 mm (G–H); 2= 0.5 mm (C–F); 3= 1mm (A–B).

Maxilliped (fig. 3A). Inner plate short; distally three robust setae intermixed with six simple setae, subdistally three simple long lateral setae; outer plate not exceeding half of posterior margin of palp article 2, with 10 marginal robust setae and six distal simple setae; palp article 3 at outer margin with one proximal and one distal group of long simple setae, with one medial long simple seta in outer margin; terminal article of palp with one simple seta along outer (upper) margin and seta at the base of nail, nail shorter than pedestal.

Gnathopod I (fig. 3C). Coxa trapezoid, broader than long, ventral and anterior margins with three and four simple setae, respectively. Anterior margin of basis with two single setae and setae in groups; posterior margin with groups of setae; ischium and merus with one posterior group of setae. Carpus 0.91 of basis length and 0.83 of propodus length; with one group of setae antero-distally and setae in rows on the proximo-posterior bulb and along postero-medial margin. Propodus slightly longer than broad, anterior margin with 10 simple setae in two groups in addition to antero-distal group with seven setae, medial surface of propodus with few setae; palm slightly convex, with one strong long palmar robust seta, two short supporting robust setae on inner surface and one short robust seta with lateral projections on outer surface. Along posterior margin of propodus with four rows of setae. Dactylus reaching posterior margin of propodus, outer and inner margins with a row of two and four simple setae, respectively, nail short, length 0.27 of total dactylus length.

FIGURE 3. Niphargus bisitunicus , sp. nov., Sarab-e- Bisitun, male 9 mm (holotype). A, MXP; B, L; C, GN 1; D, GN 2. Scale bars: 1= 0.5 mm (A–B); 2= 1mm (C–D).

Gnathopod II (fig. 3D). Coxa II rectangular, deeper than long, with nine setae along antero-ventral margin; posterior margin of basis with some setal groups and some single setae; anterior margin with single setae; posterior margin of ischium and merus with one posterior group of setae. Carpus 0.49 of the basis length and 0.75 of the propodus length; carpus with antero-distal group of setae, and setae in rows on the proximo-posterior bulb and along postero-medial margin. Propodus II larger than propodus of gnathopod I, rectangular, slightly longer than broad, anterior margin with a single seta and a pair of simple setae in addition to eight antero-distal setae, with three medial setae on surface of propodus, palm convex, with one strong palmar robust seta, with two short robust setae and one robust seta with lateral projections on inner and outer surface. Dactylus reaching posterior margin of propodus, outer and inner margins of dactylus with four simple setae each, nail length 0.24 of total dactylus length.

Coxae III–VII (fig. 4A–E). Length to width ratio in coxa III 2: 1, anterio-ventral margin with seven simple setae. Length to width ratio in coxa IV 2: 1, anterio-ventral margins with six simple setae, posterior concavity shallow and approximately 0.04 of coxa width (fig. 4B). Coxa V with anteriorly developed lobe, with one and four simple setae on anterior and posterior lobes, respectively. Coxa VI with anteriorly developed lobe, with one robust seta in anterior lobe. Coxa VII with two setae in posterior margin (fig. 4C–E).

Pereopods III–VII (fig. 4A–E). Pereopod III slightly longer than IV with length ratio of 1: 1.04 (fig. 4A, B); dactyli of pereopods III -IV short, with one robust seta and one simple seta at inner margin and one simple seta along outer margin of dactylus, in pereopod IV length of nail 0.46 of dactylus (fig. 4B).

Pereopods V: VI: VII length ratios, 1:1.31: 1.22, respectively. Pereopod VII 0.41 of body length. Bases in pereopods V–VII with six, five and six groups of robust setae along anterior margin and with 10, 10 and 11 short simple setae along posterior margin, respectively (fig. 4C–E). Postero-ventral lobe of ischium in pereopods V–VII developed. Ischium, merus and carpus in pereopods V–VII with several groups of robust and simple setae on anterior and posterior margins; propodus of pereopod VII longer than these in V and VI, dactyli of pereopods VI– VII similar to dactyli of pereopods III–IV but with shorter nail (0.3 of total dactylus length in pereopod VII) (fig. 4C–E).

Pereonites I–VII. No setae.

Pleonites I–III. With four simple setae at dorso-posterior margin.

Pleopods I–III (fig. 5A–C). Peduncle of pleopods I–III with two hooked retinacles at distal part of inner margin (fig. 5A, B); rami of pleopods I with nine to 10 articles, rami of pleopods II with seven to nine articles, rami of pleopods III with eight to 11 articles.

FIGURE 5. Niphargus bisitunicus , sp. nov., Sarab-e- Bisitun, male 9 mm (holotype). A, PL 1; B, PL 2; C, PL 3; D, USM; E, U 2; F, U 3; G, T; H, EP 1–3. Scale bars: 1= 0.5 mm (G–H); 2= 1mm (A–E); 3= 2mm (F).

Epimeral plates I–III (fig. 5H). Postero-ventral corner angular and clearly produced, posterior and ventral margins concave and convex, respectively; epimeral plates I–III with one long robust seta and two simple setae at posterior margin; ventral margin of plates II and III each with three robust setae.

Urosomites I–II (fig. 5D) Postero-dorsally with one and three robust setae, respectively and each with two simple setae dorsally.

Uropods I–III (fig. 5D–F). Peduncle in uropod I with seven and three long robust setae in dorso-lateral and dorso-medial margins, respectively. Ratio of inner to outer ramus length 1:1.06. and Inner ramus with two single robust setae laterally and five robust setae distally. Outer ramus with four groups of robust setae laterally and five robust setae distally (fig. 5D). Inner ramus in uropod II slightly longer than outer, both rami with lateral and distal long robust setae (fig. 5E). Uropod III long, almost 0.31 of body length. Peduncle of uropod III with six robust setae distally, proximal article of outer ramus with four and five groups of robust setae along inner and outer margins, respectively (fig. 5F). Proximal to distal article ratio of outer ramus 1.56: 0.56, distal article with lateral simple setae and five distal simple setae; inner ramus very short, with two distal robust setae.

Telson (fig. 5G). Deeply cleft, each lobe with three distal long robust setae, one lateral long robust seta and two lateral simple setae; length of longest apical robust seta to telson length 0.3: 1.

Etymology. The name “ bisitunicus ” refers to the type locality. Bisitun is a historical monument with a multilingual inscription on rocks of Bisitun Mountain in 25 Km west of Kermanshah City carved at 522 BC. by order of Dariush the Great, King of Persia.

Remarks and affinities. Niphargus bisitunicus is best characterized with two clearly visible characters. The first one is strongly produced epimeral plates II–III. This trait has been described from numerous species including N. hrabei , N. thermalis and N. valachicus ( Karaman 1932; Dobreanu & Manolache 1933; Dudich 1941). All these species can be easily distinguished from N. bisitunicus by pectinate dactyli of pereopods III–VII. In addition, in none of these species has been reported the second diagnostic character of N. bisitunicus , i.e. multiple robust setae on medial surface of palmar corner (supporting robust setae). This character has been so far found only in N. kenki ( Slovenia, Karaman 1952) and even in this species we noted remarkable polymorphism in this trait. If this multiple supporting robust setae seem to be rare in Europe, this is not the case in Iran. We found this trait in three herein described species (see below). However, none of them has produced epimeral plates.

Figures

FIGURE 1. Distribution map of the genus Niphargus in Iran and Middle East.